Friends (Ian pointed out that I should have sent this to the libraries list):
The page describes an improved implementation of the Typeable class, making use of polymorphic kinds. Technically it is straightforward, but it represents a non-backward-compatible change to a widely used library, so we need to make a plan for the transition.
http://hackage.haskell.org/trac/ghc/wiki/GhcKinds/PolyTypeable
Comments? You can fix typos or add issues directly in the wiki page, or discuss by email
Simon